What would the Heisenberg uncertainty principle and De Broglie wavelength be for a baseball that is not moving (i.e has zero velocity)?
Also, since macroscopic objects like baseballs have extremely small wavelengths, would this mean a high frequency? If so, would this frequency not be dangerous as it would greater than gamma and X-rays?
A first point to make is that matter waves are not electromagnetic in nature so there is no issue with people irradiating themselves with all their macroscopic possessions.
HUP says that $$\Delta p \Delta x \geq \frac{\hbar}{2}$$ When you think of this lower bound for macroscopic objects it is essentially meaningless as $\hbar$ is an incredibly small measure. As an aside a macroscopic object is constantly interacting with its environment (photons scattering off the surface etc) these interactions would cause the wave function of the object to collapse repeatedly into one state or another. Therefore QM isn't really the right language to describe the dynamics of a baseball.
Generally for very slow moving large objects the matter wave has a tiny wavelength which precludes us from being able to observe quantum effects.
